The present invention relates generally to an apparatus and method for even and controllable application of a flowable material to workpieces on assembly lines, such as automotive wheel hubs. More particularly, the present invention relates to a dispenser head assembly which employs a fixture plate for accurate and even application of a flowable material to a workpiece adjacent thereto.
It is known in several industries, such as the automotive industry, to use sealants, adhesives, corrosion resistors and other flowable materials to accomplish various mechanical functions. Adhesives, for example, are often used on threads to prevent uncoupling between adjacent threaded components such as wheel studs and lug nuts. Corrosion resistant materials are likewise applied between wheel hubs and disc rotors to prevent hub/rotor misalignment and subsequent braking degradation. Use of such materials is desirable due to the low cost of the material in relation to the high cost of damage to vehicle components in the form of repair costs and legal liability.
As these industries demand and use more flowable materials during manufacture and assembly of parts, various methods have been developed to include application of the desired material to the object part as part of the assembly process, yet simultaneously retain the speed of production of the final product and minimize the cost thereof. Accordingly, equipment is constantly custom designed to not only address the general problem of how to consistently apply the flowable material, but also the specific problem of how to adapt the application method to a particular manufacturer""s specifications.
In the past, such equipment has been designed to apply flowable products in an independent process rather than in an assembly-line type function. Heretofore, such application processes required modification in accordance with product specifications, which can vary from manufacturer to manufacturer and even within a manufacturer""s own inventory. In order to change the process, the corresponding machinery which executed the process would likewise be modified from application cycle to application cycle. Subsequently, xe2x80x9cdown timexe2x80x9d due to maintenance and modification of such machinery is prevalent, resulting in minimal production efficiency and maximum manufacturing costs.
Since the assembly line is pervasive in a multitude of industries and accordingly inherent to the proper and efficient production of a final product, it is desirable to provide a system which integrates the application method into an already existing manufacturing infrastructure. It is further desirable to design and construct appropriate corresponding equipment for accomplishing this task, wherein the machinery is easily customized to meet particular product specifications with minimal associated costs and complications.
The present invention provides an apparatus and method of applying a flowable material to a workpiece which can be integrated into an assembly line superstructure and which requires minimum maintenance and modification between application cycles. The apparatus is provided with easily machineable, replaceable and interchangeable parts which provide application capability to a multitude of workpieces without requiring modification of the parts from workpiece to workpiece, such that most workpieces can be processed using this technology.
One advantage of the present invention is the provision of a device which can be controlled to apply flowable material to a workpiece in a desired pattern. Such a device is desirable because it enables application to a variety of products in a precise, well-defined and repeatable manner.
Another advantage of the present invention is the use of a plurality of removably attached machined tubes or nozzles which deliver flowable material to a workpiece. Such tubes are desirable so that they may be easily replaced by tubes or nozzles of similar or different parameters or easily interchanged with one another so as to reduce maintenance time between application cycles.
It is yet another advantage of the present invention to provide a fixture means, such as a plate, which incorporates a plurality of holes which telescopically intercept the tubes or nozzles therethrough. Such fixture means is essential to define a predetermined clearance between an outlet through which flowable material escapes a tube or nozzle and a surface onto which such material is to be applied. Failure to define this clearance will result in uneven application of the material and subsequent mechanical malfunction. Such fixture means is further desirable to clean such tubes or nozzles between each application cycle to prevent overrun onto a workpiece surface. Removal of excess material is effected with each linear actuation of the tubes through the apertures, providing a clean tube outlet prior to each material dispensation.
It is still another advantage of the present invention to provide an associated method of controllably applying flowable material using the disclosed apparatus. During such a method, flowable material which is stored in a storage reservoir is pumped by a first pump to a second pump in fluid communication therewith. The second pump pressurizes and transfers the material to a plenum where the material is temporarily retained. The plenum is linearly moved toward a surface of the fixture means so that the tubes or nozzles affixed thereon are telescopically intercepted by corresponding apertures in the fixture means to a height where a predetermined clearance between the tube outlets and the surface of the workpiece is defined. During the linear actuation, material which has overrun from the tubes is wiped away due to the close spacing of the apertures, permitting run-off of the excess material into a separate container. Material flows from the tubes and is applied to the workpiece in a predetermined pattern which corresponds to the arrangement of the tubes. The workpiece is removed for assembly further down the assembly line, and the plenum is linearly actuated away from the fixture means to complete the application cycle.